The Terriers' reward is a fifth-round home clash against Manchester United.

Mooy was back in the first XI on Tuesday after starting the weekend's Premier League defeat at Old Trafford on the bench and the Socceroos midfielder set up the last goal of the game for Tom Ince, with a perfectly weighted through ball.

Che Adams gave Birmingham a 52nd minute lead before a Marc Roberts own goal drew Huddersfield level on 61 minutes.

Further goals from Steve Munie (94th) and Rajiv van La Parra (97th) gave Huddersfield a buffer before Ince wrapped up the scoring in the 106th minute.

Meanwhile, the FA Cup dream is over for Millwall's Australian duo James Meredith and Tim Cahill after the Lions were beaten 1-0 by Rochdale.

Unlike Cahill, who was ineligible for the fourth-round replay, left-back Meredith was included in the starting line-up but couldn't prevent Ian Henderson's 53rd minute strike sending the League One side through.

Swansea City secured the biggest FA Cup win in their history as two first-half goals each from Tammy Abraham and Nathan Dyer helped them rout Notts County 8-1 at the Liberty Stadium.

Second-half goals from Kyle Naughton, Wayne Routledge, Tom Carroll and debutant Daniel James, on as a substitute, completed the scoring.